[General Questions and Answers] CHAOS-THEORY:
ⴰⵣⵓⵍ,

When i say dead, it's typically dead.

The tablet is a Crius Mea Q7A+, uses the Qualcomm MSM8625 SoC based on the ARMv7-A arch that combines 2 ARM Cortex-A5.

While this tablet was just bricked for a long while, and i couldn't and didn't have time and firmware to reflash it, since it's one of those useless chinese low end tablets.

Having such a desirable SoC for a programmer i thought i can test on it my first steps bootloaders and Embedded OS while developing them for this sole purpose.

ⵣ Space to avoid readers jumping lines ⵣ

The tablet after i flashed it with a lower firmware of an equivalent or almost another SoC, was booting in fastboot mode only thinking that i could get more info's with that about partitions.

I didn't, so what i did was erasing the modem partition, and that left the tablet open as a generic storage drive, i saved almost every information i could have about this SoC, the partition that were available, Qualcomm's boot sequence, UART serial connection of the SoC, and read for week several pages to gather information useful to make a bootloader.

ⵣ Space to avoid readers jumping lines ⵣ

At the end i failed, i thought i could repartition the Flash memory of the SoC to prepare it for future uploading of my bootloader, there was a partition that is miss aligned, which was maybe the 3gb internal storage, so what i did is delete the partition and recreate it erasing the secondary ones, it was working normally as expected.

But then tomorrow i decided to plug the tablet again, but it doesn't get detected, this happened before, i cant really explain how the Primary core is trying to establish connection with the PC, but it's a bad mofo. Still it was detected all the time if i remember well.

But today the tablet was dead, i can even feel the SoC is not responding at all.

Not even detected when plugged to PC.

The battery does charges, cause i tested with a diode since i dont have a multimeter, which burned even with a resistor after the current was too high, but then with a DC brushless motor.

Mainly the charging circuit is separated from other components and connected directly to DC, that's why it's charging.

I opened the tablet, and took off the battery cables thinking i might be able to get the core to QDload mode which pressing some combinations...

And yeah i tried every combination i can think off, i even tried pressing my mouse in the PC and pressing the Vol UP in the tablet... am so funny.

I hope anyone can tell me a way to communicate with the SoC in this state, or any other solution thanks peace.

Finally i forgot the partition i saved as a text before i repartitioned the last ones only :

Disk /dev/sdd: 3.7 GiB, 3909091328 bytes, 7634944 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device Boot Start End Sectors Size Id Type
/dev/sdd1 * 1 40 40 20K 4d QNX4.x
/dev/sdd2 41 540 500 250K 45 unknown
/dev/sdd3 541 102940 102400 50M c W95 FAT32 (LBA)
/dev/sdd4 102941 7634943 7532003 3.6G 5 Extended
/dev/sdd5 131072 135167 4096 2M 46 unknown
/dev/sdd6 135168 141311 6144 3M 58 unknown
/dev/sdd7 141312 147455 6144 3M 4a unknown
/dev/sdd8 147456 153599 6144 3M 4b unknown
/dev/sdd9 153600 157695 4096 2M 5d unknown
/dev/sdd10 157696 165887 8192 4M 90 unknown
/dev/sdd11 165888 167935 2048 1M 63 GNU HURD or SysV
/dev/sdd12 167936 169471 1536 768K 47 unknown
/dev/sdd13 169472 196623 27152 13.3M 60 unknown
/dev/sdd14 196624 217103 20480 10M 91 unknown
/dev/sdd15 217104 413711 196608 96M 83 Linux
/dev/sdd16 413712 440863 27152 13.3M 48 unknown
/dev/sdd17 440864 1362463 921600 450M 83 Linux
/dev/sdd18 1362464 1567263 204800 100M 83 Linux
/dev/sdd19 1567264 1567303 40 20K 4c unknown
/dev/sdd20 1567304 4536903 2969600 1.4G c W95 FAT32 (LBA)
/dev/sdd21 4536904 7510599 2973696 1.4G 83 Linux
/dev/sdd22 7510600 7634942 124343 60.7M 83 Linux

As you can the sdd4 partition was overlapping other partitions sectors so i had to erase it, the rest got erased in the way, but the main boot and from 1 to 3 are intact.

Something else, the MSM7627a is a close SoC to this one, except for the one i have got 2 Cores instead of one, and supports LPDDR and have a more developed GPU, here's a note i wrote :

MSM7627 seems close enough to the MSM8625, except that it uses a single core ARMv7-A CORTEX A5.
Which is the primary core that we need to boot up, then add the next core to the equation for the kernel.

Some differences about the MSM7627a and the MSM8625 :
MSM7627a |	MSM8625
CPU Clock Speed	1,000MHz	1,200MHz
CPU Cores	1	2
GPU	Qualcomm Adreno 200	Qualcomm Adreno 203
RAM Interface	LPDDR2 SDRAM	LPDDR, LPDDR2 SDRAM

As we can see here, they are almost identical, except for the cores which wont make a wall since we're making a bootloader, the GPU... and the RAM interface

Am on Debian Stretch and i dont have any ways of visualization but i accept any link on any platform. Thanks everyone peace again

I also want to add, that i can feel a bit of heat over the tablet it's certainly not from the battery, i dont really know if its coming from the SoC, but if it is am really glad he's doing some cycles.